Controlled-impedance cable termination using compliant interconnect elements

ABSTRACT

An apparatus for terminating a controlled-impedance cable using compliant electrical contacts to provide an interface to another device. The terminator includes an anchor block for securing the cable. Optionally, the anchor block is electrically non-conductive. A conductive ferrule is installed on the cable shield and the cable end is dressed. The ferrule/cable assembly is installed in a through hole in the anchor block so the cable end is flush with the anchor block face. An insulating or conductive plate mounted to the anchor block holds the signal contact that electrically connects the center conductor to the device and optional ground contacts that electrically connect the ferrule to the device. The ground contacts surround the signal contact in a pattern that closely mimics the impedance environment of the cable. When using a conductive plate, the signal contact is insulated from the plate by an insulating centering plug or a non-conductive coating.

This application is a Reissue Application of U.S. Pat. No. 9,160,151issued on Oct. 13, 2015 from Application Ser. No. 14/534,241 filed onNov. 6, 2014. The entirety of the above-mentioned patent application ishereby incorporated by reference herein and made a part of thisapplication.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to electrical cable terminations, moreparticularly, to controlled impedance cable terminations which aregenerally used to transmit high-frequency signals in electronicequipment.

2. Description of the Related Art

The purpose of a cable termination is to provide an interconnect fromthe cable to the electrical device and to provide a separable electricalinterconnection between the cable and its operating environment. Thecharacteristic of separability means that the cables are notinterconnected by permanent mechanical means, such as soldering orbonding, but by temporary mechanical means.

Currently cables are terminated using a conventional type connectorwhich is also controlled-impedance, such as an SMA (SubMiniature VersionA) connector, or the cables are soldered to a printed circuit board(PCB) which is then separably connected to the working environment. TheSMA connectors, while being generally the same impedance environment asthe cable, have impedance mismatches which cause high-frequencyattenuation at the point of interface between the cable and theconnector and the connector and its working environment, such as like aPCB. Additionally, these cable terminations often require through holesin PCB's for mounting and, consequently, it can be difficult to designthe best possible controlled impedance environment. These types of cableterminations are generally for a single cable and require a substantialamount of PCB area to terminate, thus decreasing the density capabilityof connections.

Another form of prior art is a system which uses two independent partsto mate several cables to its electrical environment. This system usesone part that is generally soldered to a printed circuit board andanother part that is generally mated to several cables. The two piecescan be plugged together to form the controlled impedanceinterconnection. These systems are better-controlled impedanceenvironments but are limited in the densities at which the cables can beused. That is, the cables require a minimum space between them toachieve the controlled impedance environment and thus only a smallnumber of cables can be terminated in a given area.

Another form of prior art, disclosed in U.S. Pat. No. 7,544,093, is asystem which employs removable cables that are held to the device bymeans of a spring. The cable has a terminal end which makes the signalconductor protrude from the cable terminal end. The terminal is thenpressed to the device by means of a spring and the ground shield of thecable is connected to the device by a conductive rubber ground shieldthat shorts the terminal ground to the device ground.

BRIEF SUMMARY OF THE INVENTION

The present invention is an apparatus and method for terminating acontrolled-impedance cable that uses a compliant contact element at thepoint of termination minimizes detrimental electrical effects of thetermination.

The present invention includes a cable terminator that employs compliantelectrical contacts to provide an interface between thecontrolled-impedance cable (hereinafter, simply “cable”) and anotherdevice. The assembly is removably attached to the electrical device by acompression force in a direction of compression typically provided byjack screws that may not compress the assembly and device togetherlinearly. Compliant contacts compensate for noncoplanarities between theconduction points of the electrical device.

Each embodiment of the terminator includes an anchor block for securingthe cable, one or more compliant signal contacts for making theelectrical connection between the cable center conductor(s) and theelectrical device, optional compliant ground contacts for making theelectrical connection between the cable shield and the ground plane ofthe device, and a plate mounted to the anchor block that holds thecontacts.

The anchor block can be either electrically conductive or nonconductive.When conductive, the ground shield of all of the cables are electricallyconnected to the anchor block. The present invention contemplatesseveral different methods to accomplish this including soldering thecable ground shield, crimping the ground shield, potting with aconductive adhesive, insert molding, press fitting a rigidized groundshield, threading, and twist-lock. Once the cables are anchored in theanchor block, the anchor block face and cable ends are dressed to make areliable electrical contact with compliant contacts. Dressing mayinclude polishing by some mechanical means, such as by milling,grinding, or sanding, in order to make sure that the cable centerconductor is positioned at a known depth with respect to the anchorblock face.

When the anchor block is nonconductive, a conductive ferrule isinstalled on the ground shield of each cable. The cable ends are dressedto make a reliable electrical contact with compliant contacts and theferrule/cable assemblies are installed into holes in the anchor block.The present invention contemplates several different methods toaccomplish this including, press fitting, threading, and twist-lock.

Example compliant contacts for use with the present invention includespring probes, electrically-conductive rubber contacts, fuzz buttoncontacts, stamped metal contacts, chemically etched contacts, and skewedcoil contacts.

The plate holds the contacts. Features of the plate include a facesurface that abuts the anchor block face, a device surface thatgenerally abuts the device, and at least one through aperture for thecontacts. Each aperture has an anchor block face opening and a deviceface opening. The apertures for the signal contacts are aligned with thecorresponding cable hole in the anchor block.

The cable center conductor is connected to the signal conduction pointof the electrical device by the compliant signal contact. In mostconfigurations, the signal contacts are surrounded by a number of groundcontacts that connect either the conductive anchor block or the cableshield to the device in a pattern that closely mimics the impedanceenvironment of the cable. The impedance of the system can be changed bychanging the position of the ground contacts with respect to the signalcontact or by changing the insulating material.

The skewed coil contact is captured in a through aperture in the plate.The aperture has a larger center section that narrows to a smaller blockopening at the side adjacent to the anchor block and to a smaller deviceopening at the other end. The length of the contact leads is such thatthe leads extend from the openings. Alternatively, the block opening isas wide as the center section. Optionally, the contact area between thecenter conductor and device and the corresponding contact lead can beincreased by a pair of conductive bosses that the contact is captured inthat is as wide as the cable center conductor. Optionally, the remainingspace of the aperture is filled with a compliant, electricallyconductive elastomer that adds resiliency and aids in electricallyshorting the coil loops.

The fuzz button contact is cylindrical and forced into an aperture thatis narrower at the center than the ends. The contact ends extend fromthe plate.

The conductive rubber contact for the signal contact can be cylindricalwith a centrally-located annular depression that fits on an annularprotrusion in the aperture. The contact ends extend from the plate. Theconductive rubber contact for the ground contact can be the samestructure as the signal contact or can be circular, surrounding thesignal contact.

The etched or stamped contact is a strip of conductive material in a Cshape that is captured in a C-shaped aperture.

The electrical connection between the center conductor and the signalcontact and the electrical connection between the ground block/cableshield ferrule and the ground contacts are compression connections. Withthe contacts installed in the plate, the plate is mounted to the anchorblock with mechanical attachments, thereby forcing the end of the signalcontact against the end of the center conductor and the ends of theground contacts against the anchor block/cable shield ferrule.Alternatively, the electrical connection between the center conductorand the signal contact is a solder connection. Alternatively, the end ofthe center conductor is formed into a compliant spring like the skewedcoil contact.

The plate can be either insulating or conductive. The insulating plateis made of a non-electrically-conductive material. A conductive plate ispreferably composed of an electrically-conductive metal that couples theground contacts, thereby providing more precise impedance matching tothe signal contact. Alternatively, the conductive plate is composed of anon-conductive material plated with a conductive coating. The signalcontact is insulated from the conductive plate by an insulatingcentering plug or a non-conductive coating.

Alternatively, the signal contact aperture is within a conductive boss.The boss is surrounded by an insulating annulus that insulates the bossfrom the conductive plate.

Also disclosed is a method and apparatus for assembling cables to theanchor block so that the cables are the same length to within a verysmall tolerance. To facilitate the method, a soldering fixture is usedthat has a frame, a connector jig, a block jig, and legs. The frame isgenerally rectangular and stands vertically. The connector jig ismounted to the lower cross piece of the frame. The block jig is mountedto the upper cross piece of the frame. Four legs extend from the bottomcorners of the frame in generally opposite directions at an angle of atleast 10° from horizontal so that they prevent the frame from fallingover but allow the user to tilt the frame.

The connector jig locks the cable connectors at a fixed distance awayfrom where the other end of the cable will be soldered to the anchorblock. The connector jig locks the connectors in an upwardly open arc sothat the cables are the same length to the anchor block.

The anchor block is secured to the block jig, face up, which is securedto the upper cross piece. A tensioning plate is mounted to the uppercross piece. Jack screws are threaded into holes at the end of thetensioning plate.

The cable sheath is stripped and the stripped portion is fed through thehole in the anchor block and a corresponding cable hole in thetensioning plate. A coil spring is placed on each cable and a collar istightly secured to the cable.

After putting the connectors in the connector jig, the jack screws aretightened until there is adequate tension on the cables. Each cableshield is soldered to the anchor block. The angled legs allow the userto tilt the fixture for easier access to each side of the anchor block.After the solder and anchor block have cooled sufficiently, the jackscrews are loosened, and the collars, springs, and tensioning plate areremoved. The anchor block is removed from the frame and the connectorsare removed from the connector jig.

The anchor block face is finished smooth and evenly flat by sanding,milling, planing, skiving, broaching, or any other appropriate method.

Objects of the present invention will become apparent in light of thefollowing drawings and detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and object of the presentinvention, reference is made to the accompanying drawings, wherein:

FIG. 1 is an isometric view of the cable termination assembly of thepresent invention for use with coaxial cables;

FIG. 2 is a front view of the cable termination assembly of FIG. 1connected to a device;

FIG. 3 is a cross-sectional detail view of the cable terminationassembly connected to a device;

FIG. 4 is a side view of the cable termination assembly of FIG. 1;

FIG. 5 is an exploded view of the cable termination assembly of FIG. 1with a conductive anchor block;

FIG. 6 is a top cross-sectional view of the cable termination assemblyof FIG. 2 taken along the line A-A;

FIG. 7 is a front cross-sectional view of the cable termination assemblyof FIG. 4 with a conductive anchor block taken along the line B-B;

FIG. 8 is a cross-sectional view of a method of removably attaching thecable to the anchor block;

FIG. 9 is a cross-sectional view of another method of removablyattaching the cable to the anchor block;

FIG. 10 is an exploded view of the cable termination assembly of FIG. 1with a nonconductive anchor block;

FIG. 11 is a front cross-sectional view of the cable terminationassembly of FIG. 4 with a nonconductive anchor block taken along theline B-B;

FIG. 12 is a cross-sectional view showing the common features of theplate;

FIG. 13 is an isometric view of an angled anchor block;

FIG. 14 is an isometric view of a parallel anchor block;

FIG. 15 is an isometric view of a right-angle anchor block;

FIG. 16 is a cross-sectional side view of a configuration of aright-angle anchor block;

FIG. 17 is bottom view of the cable termination assembly of FIG. 1 withan insulating plate;

FIG. 18 is a detail view of a configuration of the bottom of the coaxcable termination assembly of FIG. 17 taken at C;

FIG. 19 is a detail view of another configuration of the bottom of thecoax cable termination assembly of FIG. 17 taken at C;

FIG. 20 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a skewed coil contact with a conductive anchor blockand an insulating plate having mirror-image sheets;

FIG. 21 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a skewed coil contact with a nonconductive anchorblock and an insulating plate having mirror-image sheets;

FIG. 22 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a skewed coil contact with an insulating plate havingasymmetrical sheets;

FIG. 23 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a skewed coil contact with an insulating plate havingan elongated center section;

FIG. 24 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a skewed coil contact with an insulating plate andconductive bosses;

FIG. 25 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a fuzz button contact with an insulating plate;

FIG. 26 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a conductive rubber contacts with an insulating plate;

FIG. 27 is a cross-sectional view of FIG. 26 taken at E-E;

FIG. 28 is a cross-sectional view of FIG. 27 taken at F-F;

FIG. 29 is bottom view of the cable termination assembly of FIG. 1 usingstamped or etched contacts embedded in an insulating plate;

FIG. 30 is a detail view of the bottom of the coax cable terminationassembly of FIG. 29 taken at H;

FIG. 31 is a cross-sectional view of the plate of FIG. 29 beforeinstallation on the anchor block;

FIG. 32 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using stamped or etched contacts embedded in an insulatingplate;

FIG. 33 is an exploded view of the cable termination assembly using theanchor block of FIG. 14 with an insulating plate;

FIG. 34 is a cross-sectional view of the cable termination assemblyusing the anchor block of FIG. 14 with an insulating plate;

FIG. 35 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a skewed coil contact for the ground contacts and ashaped cable center conductor for the signal contact with an insulatingplate;

FIG. 36 is bottom view of the cable termination assembly of FIG. 1 withcoaxial cables, a conductive plate, and insulating plug for the signalcontact;

FIG. 37 is a detail view of the bottom of the coax cable terminationassembly of FIG. 36 taken at J with a conductive plate and insulatingplug for the signal contact;

FIG. 38 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a skewed coil contact with a conductive plate andinsulating plug for the signal contact;

FIG. 39 is bottom view of the cable termination assembly of FIG. 1 withcoaxial cables, a conductive plate, dielectric annulus, and conductiveboss for the signal contact;

FIG. 40 is a detail view of the bottom of the coax cable terminationassembly of FIG. 39 taken at K with a conductive plate, dielectricannulus, and conductive boss for the signal contact;

FIG. 41 is a detailed view of FIG. 7 taken at D showing the coax cabletermination using a skewed coil contact with a conductive plate,dielectric annulus, and conductive boss for the signal contact;

FIG. 42 is an isometric view of the cable termination assembly of thepresent invention for use with twin-axial cables;

FIG. 43 is a front view of the cable termination assembly of FIG. 42;

FIG. 44 is a top cross-sectional view of the cable termination assemblyof FIG. 43 taken along the line M-M;

FIG. 45 is a side view of the cable termination assembly of FIG. 42;

FIG. 46 is a front cross-sectional view of the cable terminationassembly of FIG. 45 taken along the line N-N;

FIG. 47 is bottom view of the cable termination assembly of FIG. 42 withan insulating plate;

FIG. 48 is a detail view of the bottom of the cable termination assemblyof FIG. 47 taken at R with an insulating plate;

FIG. 49 is a detailed view of FIG. 46 taken at P showing the twin-axialcable termination using skewed coil contacts with an insulating plate;

FIG. 50 is bottom view of the cable termination assembly of FIG. 42 withtwin-axial cables, a conductive plate, and insulating plugs for thesignal contacts;

FIG. 51 is a detail view of the bottom of the twin-axial cabletermination assembly of FIG. 50 taken at S;

FIG. 52 is a detailed view of FIG. 46 taken at P showing the twin-axialcable termination using skewed coil contacts, a conductive plate, andinsulating plugs for the signal contacts;

FIG. 53 is a bottom view of an alternative cable termination assembly ofFIG. 42 with twin-axial cables, a conductive plate, and insulating plugsfor the signal contacts;

FIG. 54 is a detail view of the bottom of the alternative twin-axialcable termination assembly of FIG. 53 taken at T;

FIG. 55 is a detailed view of FIG. 46 taken at P showing the alternativetwin-axial cable termination of FIG. 53;

FIG. 56 is an isometric view of a soldering fixture of the presentinvention with cables and anchor block;

FIG. 57 is a front view of the fixture of FIG. 56;

FIG. 58 is a side view of the fixture of FIG. 56;

FIG. 59 is a detail view of the connector jig of FIG. 57;

FIG. 60 is a detail view of the block jig and tensioning plate of FIG.57 with the anchor block attached;

FIG. 61 is a detail view of a cable threaded through the block andtensioning plate;

FIG. 62 is a detail view of the screw and collar installed on a cable;and

FIG. 63 is a detail view of the tensioning plate in tension.

DETAILED DESCRIPTION OF THE INVENTION

The present application hereby incorporates by reference in its entiretyU.S. patent application Ser. No. 14/238,215, on which this applicationis based.

The present invention is an apparatus and method for terminating acontrolled-impedance cable that minimizes detrimental electrical effectsof the termination by using a compliant or compressible contact elementat the point of termination. With the present invention, impedancemismatches are minimized, allowing the cable to be more useful inhigh-frequency signal ranges. The present invention can be used with anycable structure where the impedance between the inner conductor(s) andthe ground shield is controlled.

In addition, the present invention increases the density at which thecontrolled-impedance cables can be used. That is, with the presentinvention, more cables can be terminated in a given amount of space thanwith terminations of the prior art. Further, the interface between thecomponents of the present invention may not require through-holemounting, which may further enhance density capability.

The present invention calls for proper dressing of the cable end so thatsmall, compliant contacts can be used for separably interconnecting thecontrolled-impedance cables to whatever electrical device the userdesires. A prime example is connecting two printed circuit boards whichmust communicate with each other at high frequency, such as connecting acomputer central processing PCB with its random access memory PCB oranother central processing PCB.

As shown in FIGS. 1-11, the present invention includes a cableterminator 10 that employs compliant electrical contacts 12, 14 toprovide an interface between the controlled-impedance cable(hereinafter, simply “cable”) 30 and another device 2, typically anintegrated circuit (IC) or a printed circuit board (PCB). The terminator10 is installed on the cable 30 as described below. The combination ofterminator 10 and cable(s) is referred to as the cable terminationassembly 8. As shown in FIGS. 2 and 3, the assembly 8 is removablyattached to the electrical device 2 by a compression force 22 in adirection of compression 24. Typically, jack screws 26 provide thecompression force 22. Jack screws 26 may not compress the assembly 8 andthe electrical device 2 together linearly. Compliant contacts 12, 14facilitate an adequate connection between the cables 30 and theelectrical device 2, compensating for noncoplanarities in the conductionpoints 4 of the electrical device 2.

The present invention is for use with controlled-impedance cables havingone or more center conductors. A coaxial cable 30 has a center conductor32 surrounded by a dielectric 34 with a ground reference shield 36outside the dielectric 34. Optionally, a sheath 38 covers the shield 36.A twin-axial cable 30 has two center conductors 32 surrounded by adielectric 34 with a ground reference shield 36 outside the dielectric34 and a sheath 38 covering the shield 36. Cables with more than twocenter conductors are available. Although not specifically described,the present invention can be adapted to accommodate cables having morethan two center conductors.

The terminator 10 of the present invention has several embodiments. Eachembodiment includes an anchor block 16 for securing the cable 30, one ormore compliant signal contacts 12 for making the electrical connectionbetween the cable center conductor(s) 32 and the electrical device 2,optional compliant ground contacts 14 for making the electricalconnection between the cable shield 36 and the ground plane of thedevice 2, and a plate 18 mounted to the anchor block 16 that holds thecontacts 12, 14.

In one embodiment, the anchor block 16 is conductive and provides acommon ground for the cables 30, as in FIG. 5. The ground shields 36 ofall of the cables 30 are electrically connected to the anchor block 16.The present invention contemplates several different methods toaccomplish this. The ground shield 36 may be soldered into a hole 40 inanchor block 16. The cable sheath 38 is stripped back at least thelength of the anchor block hole 40. The cable 30 is inserted into thehole 40 up to the end of the sheath 38 and the shield 36 is soldered tothe anchor block 16.

Alternatively, the cable 30 may be crimped into the anchor block hole40. After the sheath 38 is stripped back, the cable 30 is inserted intothe hole 40. The hole 40 may have the path through which the cable 30runs geometrically altered after insertion of the cable 30 to a pointwhere the size of the path is smaller than the size of the cable 30,thereby anchoring the cable 30 to the anchor block 16 and electricallyconnecting the shield 36 to the anchor block 16.

Other methods of anchoring the cable 30 to the anchor block 16 includepotting the ground shield 36 with a conductive adhesive once it isplaced in the hole 40, insert molding the anchor block 16 with the cable30 in place at the time of molding, and press fitting a rigidized, forexample, pretinned, ground shield into the hole 40.

Once the cables 30 are anchored in the anchor block 16, the face 20 ofthe anchor block 16 and cable ends 136 are properly dressed to make areliable electrical contact with small compliant contacts. The cableends 136 and the anchor block face 20 may need to be polished andplanarized by some mechanical means, such as by milling, grinding, orsanding, in order to make sure that the cable center conductor 32 ispositioned at a known depth with respect to the anchor block face 20, inthis case flush with the anchor block face 20. The cable ends 136 andface 20 may also require noble metal plating to prevent the polishedsurface from oxidizing or otherwise degrading so as to inhibitacceptable electrical connection to the center conductor 32 and theanchor block 16.

Methods of removably attaching the cable 30 to the anchor block 16 areshown in FIGS. 8 and 9. These methods permit replacement of individualcables 30 so the entire assembly does not have to be replaced. The firstmethod calls for attaching a ferrule at or near the end of the cable 30for dressing the cable end. The sheath 38 is stripped back and athreaded ferrule 134 is slipped over the shield 36. The ferrule 134 isattached to the cable by soldering, crimping, or other mechanical meansthat electrically couples the ferrule 134 to the shield 36. The cableend 136 is then dressed by polishing so as to achieve a flat surface onthe cable end 136. The ferrule 134 is then threaded into a threaded hole138 in the anchor block 16 until the center conductor 32 is pressed tothe signal contact 12 in order to produce an electrical connectionbetween the center conductor 32 and the signal contact 12.

In the configuration of FIG. 8, the anchor block 16 has two parts 140,142. The top part 140 has the threaded hole 138 into which the ferrule13 is threaded. The bottom part 142 is for precisely aligning the cableend 136 so that the center conductor 32 is directly over the signalcontact 12. This method can be use for precisely terminating individualcable on very tight pitch as in 1 mm or less spacing between cablecenter conductors 32.

The second method of removably attaching the cable 30 to the anchorblock 16 calls for the use of a twist-lock attachment 300, as shown inFIG. 9. A twist-lock component 302 is slipped over the cable 30 suchthat the component 302 can slide freely over the cable 30. A coil spring304 is slipped over the cable 30. After the sheath 38 is stripped back,a ferrule 306 is attached to the shield 36 by soldering, crimping, orother mechanical means that electrically couples the ferrule 306 to theshield 36. The cable end 308 is then dressed by polishing so as toachieve a flat surface on the cable end 308.

The cable end 308 is inserted into a hole 310 in the anchor block 16.Protrusions 312 from the twist-lock component 302 slide down opposednotches, not shown, in the sides of the hole 310 until they align withan annular depression 316 in the hole 310. With this alignment, thespring 304 is compressed so that it presses the center conductor 32 tothe signal contact 12 in order to produce an electrical connectionbetween the center conductor 32 and the signal contact 12. Thetwist-lock component 302 is turned so that the protrusions 312 arecaptured by the annular depression 316, thereby retaining the cable 30in the hole 310.

In another embodiment, the anchor block 16 is nonconductive and merelyprovides an anchor for the cables 30, as in FIGS. 10 and 11. The anchorblock 16 is composed of a nonconductive material. The cable sheath 38 isstripped back and an electrically-conductive ferrule 330 is slipped overthe shield 36. The ferrule 330 is attached to the cable by soldering,crimping, or other mechanical means that electrically couples theferrule 330 to the shield 36.

The cable end 332 is then dressed by polishing so as to achieve a flatsurface on the cable end 332. The ferrule 330 is then inserted into ahole 334 in the anchor block 16 until the center conductor 32 is pressedto the signal contact 12 and the ferrule 330 is pressed against theground contacts 14.

The present invention contemplates a number of different ways for theferrule/cable assembly to be retained in the anchor block 16. Two suchmethods are described above with reference to removable cables and FIGS.8 and 9. The first uses a threaded attachment and the second uses atwist-lock attachment.

Another method is via a press fit. Optionally, the side 340 of theferrule 330 is knurled or otherwise roughened. The ferrule/cableassembly is forced into the hole 334, which is slightly smaller, untilthe cable end 332 is flush with the block face 338.

Another method is shown in FIG. 11. The ferrule 330 has an annular ridge342 either at the end 344 of the ferrule 330 or away from the end 344,as in FIG. 11. The anchor block 16 has two sections, a bottom section346 and a top section 348. The upper end of the hole 334 in the bottomsection 346 has an annular groove 352. When the ferrule/cable assemblyis inserted into the hole 334, the ridge 342 fits into the groove 352with the cable end 332 flush with the block face 338. The block topsection 348 is installed on the bottom section 346 and attached viascrews, clips, or any other acceptable method. The top section 348captures the ferrule/cable assembly in the anchor block 16. Optionally,the ridge 342 and groove 352 can be keyed to prevent the ferrule/cableassembly from rotating in the hole 334.

In some designs, particularly with removable attachments, the cable endmay not be exactly flush with the anchor block face 20, that is, it maybe slightly recessed into or protruding from the anchor block face 20.That recession or protrusion can be as much as 0.05 inch. The presentspecification and claims use the term, “flush”, to indicate that thecable end is actually flush with, slightly recessed into, or slightlyprotruding from the anchor block face 20 by as much as 0.05 inch.

In most of the present figures, the anchor block 16 is generally arectangular solid where the cables 30 are perpendicular to the anchorblock face 20. However, the anchor block 16 can have other shapes. FIG.13 shows an angled anchor block 16 where the cables 30 are at an angleto the anchor block face 20. FIG. 14 shows a parallel anchor block 16that can be used with a device edge attachment.

FIG. 15 shows a generic right angle anchor block 16 where the cables 30bends through 90°. FIG. 16 shows a right angle anchor block 16 with astrain relief. The anchor block 16 has a base 280 that is composed of aconductive or non-conductive, generally rigid material. The cable 30rests in a channel 284 in the base 280. A cover 282 that is composed ofa conductive or non-conductive, relatively rigid material is attached tothe base 280. The manner of attachment depends on the base and covermaterials. For example, if the base 280 and cover 282 are both metallic,the attachment can be by screws. If the base 280 and cover 282 are bothplastic, the attachment can be the cover 282 snapping onto the base 280with tabs and slots. The channel 284 has a bend 286 that provides strainrelief when the base 280 and cover 282 are assembled.

These are only examples of other anchor block shapes. The presentinvention contemplates that the anchor block 16 can have any shape thatworks for a particular application.

Example compliant contacts for use with the present invention includespring probes, electrically-conductive rubber contacts, fuzz buttoncontacts, stamped metal contacts, chemically etched contacts, and skewedcoil contacts.

A typical spring probe consists of a hollow barrel with a spring and oneor two plungers. The spring is housed in the barrel with the end of theplungers crimped in opposed open ends of the barrel at the ends of thespring. The spring biases the plungers outwardly, thereby providing aspring force to the tip of the plungers.

Conductive elastomer bumps are made of rubber and/or silicones ofvarying types with embedded conductive metal elements. The elastomerbump can work when the device conduction point is elevated off thedevice, thus sometimes requiring a protruding feature from the device orthe addition of a third conductive element to the system to act as aprotruding member.

Alternatively, the contact can be made of a single sheet of anisotropicconductive elastomer which is an elastomeric sheet that only conductselectricity through its thickness.

A fuzz button is a wire that is crumpled into a cylindrical shape. Theresulting shape looks very much like tiny cylinder made of steel wool.When the cylinder is placed within a hole in a sheet of nonconductivematerial, it acts like a spring that is continuously electricallyshorted. Like elastomer bumps, the fuzz button can be used with a thirdelement needed to reach inside the hole of the nonconductive sheet tomake contact with the fuzz button.

Skewed coil contacts of various types and configurations are describedin U.S. Pat. Nos. 7,126,062 and Re41,663, both of which are incorporatedherein by reference. Briefly, the skewed coil contact includes a coil ofconductive, inherently elastic wire with a pair of oppositely extendingleads. The leads extend in a direction angled from the coil axis. Duringcompression, the coil loops are electrically shorted together while theyslide along each other.

The figures illustrate the use of skewed coil contacts, fuzz buttoncontacts, conductive rubber contacts, and stamped metal or a chemicallyetched contacts. As indicated above, the plate 18 holds the contacts 12,14. The structure of the plate 18 depends on the type of contact.Regardless of the type of contact, the plate 18 has several commonfeatures. These features are shown in FIG. 12 with reference to theskewed coil contact as a signal contact 12, but apply to all types ofcontacts as well as the ground contacts 14. The plate 18 has a facesurface 170 that abuts the anchor block face 20 when the terminator 10is assembled. The plate 18 has a device surface 172 that generally abutsthe device 2 when the terminator 10 is connected to the device 2. Theplate 18 has at least one through aperture 174 for the contacts 12, 14.The apertures are either signal apertures or ground apertures, dependingon the type of signal that is carried in the contact in that aperture.Each aperture 174 has an anchor block face opening 176 and a device faceopening 178. The signal apertures for the signal contacts 12 are alignedwith the corresponding cable hole 40 in the anchor block 16. Prior toassembling the plate 18 to the anchor block 16, the anchor block contactpoint 180 of the contact 12 extends from the anchor block face opening176. Prior to connecting the terminator 10 to the device 2, the devicecontact point 182 of the contact 12 extends from the device face opening178.

FIGS. 17-41 show configurations of the present invention for a coaxialcable. The center conductor 32 of the cable 30 is connected to thesignal conduction point 4 of the electrical device 2 by the compliantsignal contact 12. As shown in FIGS. 17-19, the signal contacts 12 aresurrounded by a number of ground contacts 14 that connect either theconducting anchor block 16 or the cable ferrule 330 to the device in apattern that closely mimics the impedance environment of the cable 30,e.g. 50 ohms, 75 ohms, 85 ohms, or 100 ohms. The impedance of the systemcan be changed by changing the position of the ground contacts 14 withrespect to the signal contact 12 or by changing the insulating material,thereby changing the dielectric constant of the material or both.Changing the locations of the ground contacts with respect to the signalcontact is like changing the diameter of the ground shield on a coaxialcable from 2.5 mm for 50-ohm cable to 6 mm for 75-ohm cable.Alternatively, the dielectric may be changed so that the lower thedielectric constant of the material, the closer the ground shield can beto the cable signal conductor while the cable maintains the sameimpedance environment.

When there are two or more cables 30 and a conductive anchor block 16,there may be ground contacts 14 that are “shared” between cables 30. Forexample, in the coaxial structure of FIG. 19, the ground contact 14′between the two signal contacts 12 is common to both cables. The commonground contact can also been seen in FIG. 20, where the right sideground contact 14 is between the ground shields 36 of adjacent cables30. Another example is shown in the twin-axial structure of FIG. 48,where the ground contacts 14′ between the two signal contacts ofadjacent cables 30 are common to both cables.

As shown in FIGS. 20-22, the skewed coil contact 42 is captured in athrough aperture 44 in the plate 18. The aperture 44 has a larger centersection 48 that narrows to a smaller block opening 46b at the sideadjacent to the anchor block 16 and to a smaller device opening 46a atthe other end. In one configuration, shown in FIGS. 20 and 21, the plate18 has two mirror image sheets 50 where each sheet 50 has one opening46a, 46b and a half of the center section 48. The contact 42 is placedin the center section 48 of one sheet 50 and the sheets 50 aresandwiched together to capture the contact 42. In another configuration,shown in FIG. 22, the plate 18 has a base sheet 52 with one of theopenings 46a and the center section 48 and a top sheet 54 with the otheropening 46b. The contact 42 is placed in the center section 48 and thesheets 52, 54 are sandwiched together, capturing the contact 42 withinthe aperture 44. The length of the contact leads 56 is such that theleads 56 extend from the openings 46a, 46b.

An alternative configuration is shown in FIG. 23. Rather than a widercenter section with smaller openings at both ends, the center section 48extends its full width from the block opening 46b to a smaller deviceopening 46a on the opposite side of the plate 18 from the anchor block16. When the plate 18 is mounted to the anchor block 16, as describedbelow, the contact 12, 14 is secured in the plate 18. If all of theapertures 44 are of this design, the plate 18 does not have to have twosheets 50. Since the contacts 12, 14 can be installed from the blockopening 46b, the plate 18 can be a single sheet.

Because of the very small size of the wire used to make the skewed coilcontact 42, the contact area between the skewed coil signal contact 12and the cable center conductor 32 is small. This can cause a capacitivereactance at the interface of the contact leg 56 and the cable centerconductor 32 which can cause reflections at high frequencies. To helpalleviate this problem, the through aperture 44 is wide for its entirelength, as in FIG. 24. Each end has an annular shoulder 60. A pair ofconductive bosses 62 with a shoulder 64 fit into the aperture 44, withthe shoulders 60, 64 retaining the bosses 62 in the aperture 44. Theboss 62 has a through hole 66 that narrows from the center of theaperture 44 to a smaller device opening 46a and a smaller block opening46a at the ends through which the contact leads 56 extend. The bosses 62increase the effective area of the contact lead 56.

In FIG. 24, the conductive bosses 62 are shown spaced from each other,that is, they do not touch each other. In an alternative configuration,the conductive bosses 62 are made long enough to touch each other,either around the entire circumference of the aperture 44 or onlyportions of the circumference, such as with extending fingers. This canalleviate the potential problem of the conductive bosses 62 acting as acapacitive device if the contact 12 does not short them together.

Optionally, in any skewed coil contact configuration, after the contact42 is installed, the remaining space of the aperture 44 is filled with acompliant, electrically conductive elastomer that adds resiliency andaids in electrically shorting the coil loops.

As shown in FIG. 25, the fuzz button contact 70 is cylindrical. Theplate 18 has a through aperture 72 that is narrower at the center thanthe ends, as at 74. The contact 70 is forced into the aperture 72. Thelength of the contact 70 is such that the ends 76 extend from the plate18.

As shown in FIGS. 26-28, the conductive rubber contact 100 for thesignal contact 12 can be cylindrical with a centrally-located annulardepression 102. The plate 18 has a through aperture 104 with acentrally-located annular protrusion 106. The rubber contact 100 isradially compressed and placed in the aperture 104 such that theprotrusion 106 fits into the depression 102 to retain the contact 100 inthe aperture. The length of the contact 100 is such that the ends 108extend from the plate 18.

The conductive rubber contact for the ground contact 14 can be of thesame structure as the signal contact 12. Alternatively, the conductiverubber contact 112 for the ground contact 14 is circular, surroundingthe signal contact 12, as in FIG. 27. The conductive rubber contact 112has a circular top sheet 114 adjacent to the anchor block 16 and acircular bottom sheet 116 for interfacing to the device 2. The twosheets 114, 116 are electrically connected by a plurality of plugs 118in through apertures 120 in the plate 18. The number of plugs 118 canvary by application and is typically four or eight spaced evenly aroundthe signal contact 100. As with the signal contact 100, each plug 118has an annular depression 122 that fits into an annular protrusion 124for retention. Optionally, knobs 126 extending from the sheets 114, 116into depressions 128 in the plate 18, as in FIG. 28, help retain thesheets 114, 116 in position.

In FIGS. 29-32, the contact 150 is a strip of conductive material in a Cshape. The contact 150 can be formed by chemical etching, by stampingand forming, or by any other means practical. The contact 150 iscaptured in a through aperture 160 in the plate 18. In their quiescentstate, the contact leads 152 extend outwardly of the plate 18, as inFIG. 31. When the anchor block 16 is attached to the plate 18, the upperlead 152 deforms toward the plate 18 and into a depression 156, as inFIG. 32, thereby providing electrical contact by the signal contact 12to the center conductor 32 and by the ground contacts 14 to the anchorblock 16. When the assembly is connected to the device 2, the lower lead154 deforms toward the plate 18 and into a depression 158.

An alternate terminator assembly 10 using the anchor block of FIG. 14 isshown in FIGS. 33 and 34. The compliant contacts 12, 14 fit intoapertures 44 in the plate 18. The signal contact 12 presses against thecenter conductor 32 that has been bisected longitudinally and dressed.

The electrical connection 80 between the center conductor 32 and thesignal contact 12 and the electrical connection 82 between the anchorblock 16 and the ground contacts 14 are compression connections. Withthe contacts 12, 14 installed in the plate 18, the plate 18 is mountedto the anchor block 16 with mechanical attachments 28, such as screws,rivets, and the like. Installing the plate 18 forces the end of thesignal contact 12 against the end of the center conductor 32 and forcesthe ends of the ground contacts 14 against the anchor block 16.

Alternatively, the electrical connection 80 between the center conductor32 and the signal contact 12 is a solder connection while the electricalconnection 82 between the anchor block 16 and the ground contacts 14 isa compression connection.

Alternatively, as shown in FIG. 35, the end of the center conductor 32is formed into a compliant spring like the skewed coil contact, as at84. The plate 18 is configured like that of FIG. 23, where the blockopening 46b is the same size as the center section 48. The plate 18 isassembled without a signal contact 12 and, when the plate 18 isinstalled, the end of the center conductor 32 extends through the deviceopening 46a. The electrical connection 82 between the anchor block 16and the ground contacts 14 is a compression connection.

The plate 18 can be either insulating or conductive. FIGS. 20-35 show aninsulating plate 86. The insulating plate 86 is made of anon-electrically-conductive material, preferably a plastic, so as to notelectrically couple the signal contacts 12 and ground contacts 14.

A conductive plate 88, shown in FIGS. 36-41, is preferably composed ofan electrically-conductive metal. Alternatively, the conductive plate iscomposed of a non-conductive material plated with a conductive coating.The conductive plate 88 electrically couples the ground contacts 14,thus providing more precise impedance matching to the signal contact 12.The signal contact 12 is insulated from the conductive plate 88 by aninsulating centering plug 90 which prevents the signal contact 12 fromelectrically shorting to the conductive plate 88. The plug 90 includesthe through aperture 44, the device opening 46a, the anchor blockopening 46b, and the center section 48. The plug 90 is typically madefrom an insulating plastic.

The plug 90 may be press fit into a through hole 92 in the conductiveplate 88 or it may be bonded into the hole 92 with an adhesive.Alternatively, as shown in FIG. 38, the plug 90 is has two parts 94,each of which fit into one plate sheet 50. Mating shoulders 96, 98retain the plug parts 94 in the plate sheets 50.

FIGS. 39-41 show a configuration where the signal contact aperture 44 iswithin a conductive boss 190, like that of FIG. 24. The boss 190 issurrounded by an insulating annulus 192 that insulates the conductiveboss 190 from the conductive plate 88. The annulus 192 can be composedof any dielectric material, but a better match can be had if the annulus192 is composed of the same material as the cable dielectric 34.

Alternatively, the signal contact 12 can be insulated from theconductive plate 88 by a non-conductive coating such as powder coating.In this case the signal contact aperture may be made larger such thatthe coating reduces the aperture size to the appropriate size for use.As with the plug 90, the impedance of the system can be changed byeither changing the thickness of the coating or by changing the coatingmaterial, thereby changing the dielectric constant of the material.

FIGS. 42-55 show configurations of the present invention for atwin-axial cable. The twin-axial configurations are illustrated usingthe skewed coil contacts. The present invention contemplates that any ofthe various available compliant contacts, including those described withreference to the coaxial cable assembly, can be used with twin-axialcables, as well as cables with more than two center conductors.

The center conductors 32 of the cable 30 are connected to the signalconduction points 4 of the electrical device 2 by the compliant signalcontacts 12. As shown in FIGS. 47-52, the signal contacts 12 aresurrounded by a number of ground contacts 14 in a pattern that closelymimics the impedance environment of the cable 30, e.g. 50 ohms, 75 ohms,85 ohms, or 100 ohms. As described above with reference to the coaxialcable assembly, the impedance of the system can be changed by changingthe position of the ground contacts 14 with respect to the signalcontact 12 or by changing the insulating material, thereby changing thedielectric constant of the material or both.

As with the coaxial cable configurations, the plate 18 can be eitherinsulating or conductive. FIGS. 47-49 show an insulating plate 86 andFIGS. 50-55 show a conductive plate 88. With the conductive plate 88,the signal contacts 12 are insulated from the conductive plate 88 by aninsulating plug 90 which prevents the signal contacts 12 fromelectrically shorting to the conductive plate 88. The plug 90 has twoapertures 44, one for each signal contact 12. As described above withreference to FIGS. 36-38, the twin-axial cable plug 90 can be anchoredby any conceivable means, such as by press fit, as shown in FIG. 52,adhesive, or capture.

FIGS. 53-55 show an alternative to the configuration of FIGS. 50-52.This configuration does not use ground contacts, only signal contacts12. The ground signal conducts directly through the conductive plate 88to the device 2.

The present specification describes a number of different compliantcontacts that can be used in the present invention. These are merelyexamples. The present invention contemplates that any form of compliantcontact that has the appropriate characteristics for the particularapplication can be used. In addition, the present specificationcontemplates that different types of contacts can be use in the sameassembly. For example, a skewed coil contact can be used as the signalcontact and a circular conductive rubber contact can be used as theground contact.

The present invention produces a controlled-impedance, compliant cableto device interface which can be less than 1 mm thick (the length of thecompliant contacts 12, 14) and mimics the controlled-impedanceenvironment of the cable 30, thereby ensuring the highest possiblesignal rates through the termination.

The present invention can also produce a controlled-impedance device todevice interface because the cables 30 can have terminators 10 at bothends.

When working with very high frequencies, for example, frequencies in theGigahertz range and above, electrical cable lengths are very critical.In order to maintain phase synchronization between signals on differentcables, the cables must have as close to the exact same length,mechanically and electrically, as is practical. The presentspecification describes a method and apparatus for assembling cables 202to the anchor block 200 so that the cables 202 are the same length towithin a very small tolerance, on the order of 0.001 inch for cables 202that are 6 inches long from the cable connector 204 to the block face206. The present method can be used for cables of any length. Longercables result in larger tolerances. At a given temperature, a cablelength can be controlled to within 0.03% to 0.05% of the cable's overalllength.

To facilitate the method, a soldering fixture 210 is used. The fixtureincludes a frame 212, a connector jig 214, a block jig 216, and legs218. FIGS. 56-58 illustrate a fixture 210 for use with 16 cables 202 anda rectangular solid anchor block 200 for two rows of cables 202. Thefixture 210 can be modified for a different number of cables, differentshape anchor block 200, different cable connector 204, different cablelength, etc.

The frame 212 is generally rectangular and stands vertically. Theconnector jig 214 is mounted to the lower cross piece 222 of the frame212 inside the frame 212. The block jig 216 is mounted to the uppercross piece 224 of the frame 212 outside of the frame 212. Four legs 218extend from the bottom corners of the frame 212 in generally oppositedirections. The legs 218 are angled from the frame 212 by at least 10°from horizontal so that they prevent the frame 212 from falling over butallow the user to tilt the frame 212. The preferred angle is about 20°so that the frame can be tilted between 70°, 90°, and 110° from verticalto facilitate use, as described below. The present inventioncontemplates that the angle of the legs 218 can vary from application toapplication.

The fixture 210 locks the connector 204 of each cable 202 at a fixeddistance away from where the other end of the cable 202 will be solderedto the anchor block 200. The connector jig 214 locks the connectors 204and can be designed appropriately for any particular type of connector204. FIG. 59 shows a portion of a connector jig 214 for locking coaxialconnectors. There is a connector securement 226 for each cable 202. Thesecurement 226 includes a channel 228 with an upper narrow section 230for the cable 202 and a lower wide section 232 for the connector 204.The narrow section 230 is defined by outwardly extending upper fingers234. The wide section 232 is defined by outwardly extending lowerfingers 236. When there is upward tension on the cable 202, theconnector 204 catches on the bottom surface 238 of the upper fingers234.

Because the distance (pitch) between cables 202 at the anchor block 200is smaller than the diameter of the connectors 204, the cables 202cannot be secured parallel to each other to achieve equal length. Tosolve this problem, the connector jig 214 locks the connectors 204 in anupwardly open arc 240 so that the cables 202 are the same length to theanchor block 200.

As shown in FIG. 60, the block jig 216, a C-shaped component, is securedby screws 250 to the top surface 244 of the upper cross piece 224 of theframe 212, straddling a C-shaped cutout 246. The anchor block 200 issecured by screws 242 to the block jig 216 such that the anchor blockface 206 is up and straddles the cutout 246, which provides access tothe cable holes 248 in the anchor block 200.

A tensioning plate 252 is mounted to the upper cross piece 224. Thereare threaded holes 254 at each end of the tensioning plate 252 intowhich the jack screws 256 are threaded. The tensioning plate 252 isplaced over the anchor block face 206 and the jack screws 256 are turnedinto the holes 254 so that the tensioning plate 252 rests on the anchorblock face 206. The tensioning plate 252 has a cable hole 258 for eachcable 202 that is aligned with the anchor block cable hole 248 for thesame cable 202. Optionally, the tensioning plate 252 is machined outabove the anchor block 200, as at 270, to facilitate access to the face206.

Each cable 202 is trimmed so that it is at least 1.4 inches longer thatthe assembled length of the cable 202. The cable 202 is stripped at theend so that the length from the connector 204 to the stripped portionremains constant. The non-stripped portion of the cable 202 extends intothe anchor block hole 248 approximately 0.06 inches.

As shown in FIG. 61, after trimming, each cable 202 is fed through thehole 248 in the anchor block 200 corresponding to the connectorsecurement 228 into which the cable connector 204 will be placed andthrough the corresponding cable hole 258 in the tensioning plate 252.

As shown in FIG. 62, a coil spring 260 is placed on each cable 202 and acollar 262 is placed over each cable 202 so it touches the spring 260.Alternatively, the spring 260 and collar 202 can be a unified component.A set screw 264 is turned into the collar 262 to tightly secure thecollar 262 to the cable 202.

The connectors 204 are placed into the corresponding securement 228 andthe two jack screws 256 are tightened until the cables 202 have enoughtension to be pulled against their securements 226, making sure that thecables 202 are straight between the connector 204 and the anchor block200 with no kinks or bends. Optional stops 266 prevent the jack screws256 from being tightened too much. In the illustrated configuration, thestops 266 are spacers 292 on the jack screws 256 between the tensioningplate 252 and the jack screw heads 294, as shown in FIG. 63.

The springs 260 independently keep each cable 202 tight so that thedistance from the connector 204 anchor block face 206 remains consistentfor all of the cables 202.

Each cable shield 208 is soldered to the anchor block 200 such that thesolder flows into the hole 248. The angled legs 218 allowing the user totilt the fixture 210 permit easier access to each side of the anchorblock 200 for soldering.

After the solder and anchor block 200 have cooled sufficiently, the jackscrews 256 are loosened until tension on the springs 260 is released.The collars 262, springs 260, and tensioning plate 252 are removed. Theanchor block 200 is removed from the frame 212 and the connectors 204are removed from the connector jig 214. The excess cable is cut off.

Next, the anchor block face 206 is finished smooth and evenly flat.There are a number of ways known in the art to accomplish this,including sanding, milling, planing, skiving, and broaching. Once thecables 202 are secured in the anchor block 200, any conceivable methodcan be used to dress the face 206 of the anchor block 200 which achievesthe desired surface finish and/or planarity.

Thus it has been shown and described a controlled-impedance cabletermination and a method and apparatus for attachingcontrolled-impedance cables to the termination. Since certain changesmay be made in the present disclosure without departing from the scopeof the present invention, it is intended that all matter described inthe foregoing specification and shown in the accompanying drawings beinterpreted as illustrative and not in a limiting sense.

What is claimed is:
 1. A controlled-impedance cable termination for acontrolled-impedance cable, the cable comprising at least one centerconductor, a dielectric surrounding the at least one center conductor,and a ground shield surrounding the dielectric, the terminationcomprising: (a) an anchor block having a face and at least one cablethrough hole, the cable through hole having an opening in the face; (b)a electrically-conductive ferrule adapted to be installed on the groundshield at the end of the cable, the ferrule adapted to be captured inthe cable through hole such that the at least one center conductor andthe dielectric are flush with the face of the block; (c) a plateattached to the face, the plate having a face surface abutting the faceand a device surface, the plate including at least one signal throughaperture extending between the face surface and the device surface, thesignal through aperture having a signal block opening adjacent to andaligned with the cable through hole opening, the signal through aperturehaving a signal device opening in the device face surface; and (d) anelectrically-conductive compliant signal contact captured within each ofthe at least one signal through aperture, the signal contact having asignal block contact point extending from the signal block opening and asignal device contact point extending from the signal device opening. 2.The cable termination of claim 1 wherein the anchor block is composed ofan electrically-nonconductive material.
 3. The cable termination ofclaim 1 wherein the ferrule is captured in the cable through hole by apress fit.
 4. The cable termination of claim 1 wherein the ferrule isremovably captured in the cable through hole.
 5. The cable terminationof claim 1 wherein the plate is composed of an electrically insulatingmaterial and the cable termination further comprises: (a) the plateincluding a plurality of ground through apertures spaced from andsurrounding the at least one signal aperture, each of the groundapertures extending between the face surface and the device surface, theground apertures each having an anchor block opening in the face surfaceand a ground device opening in the device face; and (b) anelectrically-conductive compliant ground contact captured within each ofthe ground apertures, the ground contact having an anchor block contactpoint extending from the anchor block opening into electrical contactwith the ferrule and a ground device contact point extending from theground device opening.
 6. The cable termination of claim 1 wherein theplate is composed of an electrically-conductive material and the signalaperture is within an electrically-nonconductive plug in the plate. 7.The cable termination of claim 6 further comprising: (a) the plateincluding a plurality of ground through apertures spaced from andsurrounding the at least one signal aperture, each of the groundapertures extending between the face surface and the device surface, theground apertures each having an anchor block opening in the face surfaceand a ground device opening in the device face; and (b) anelectrically-conductive compliant ground contact captured within each ofthe ground apertures, the ground contact having a ferrule contact pointextending from the anchor block opening into electrical contact with theferrule and a ground device contact point extending from the grounddevice opening.
 8. A controlled-impedance cable termination assemblycomprising: (a) at least one controlled-impedance cable having at leastone center conductor, a dielectric surrounding the center conductor, anda ground shield surrounding the dielectric; (b) an anchor block having aface and at least one cable through hole, the cable through hole havingan opening in the face; (c) an electrically-conductive ferrule installedon the ground shield at the end of the cable to form a ferrule/cableassembly, the ferrule/cable assembly captured in the cable through holesuch that the cable end is center conductor and the dielectric are flushwith the block face; (d) a plate attached to the face, the plate havinga face surface abutting the face and a device surface, the plateincluding at least one signal through aperture extending between theface surface and the device surface, the signal through aperture havinga signal block opening adjacent to and aligned with the cable centerconductor, the signal through aperture having a signal device opening inthe device face surface; and (e) an electrically-conductive compliantsignal contact captured within each of the at least one signal throughaperture, the signal contact having a signal block contact pointextending from the signal block opening into electrical contact with thecenter conductor and a signal device contact point extending from thesignal device opening.
 9. The cable termination of claim 8 wherein theanchor block is composed of an electrically-nonconductive material. 10.The cable termination of claim 8 wherein the ferrule is captured in thecable through hole by a press fit.
 11. The cable termination of claim 8wherein the ferrule is removably captured in the cable through hole. 12.The cable termination of claim 8 wherein the plate is composed of anelectrically-insulating material and the cable termination furthercomprises: (a) the plate including a plurality of ground throughapertures spaced from and surrounding the at least one signal aperture,each of the ground apertures extending between the face surface and thedevice surface, the ground apertures each having an anchor block openingin the face surface and a ground device opening in the device face; and(b) an electrically-conductive compliant ground contact captured withineach of the ground apertures, the ground contact having an anchor blockcontact point extending from the anchor block opening into electricalcontact with the ferrule and a ground device contact point extendingfrom the ground device opening.
 13. The cable termination of claim 8wherein the plate is composed of an electrically-conductive material andthe signal aperture is within an electrically-nonconductive plug in theplate.
 14. The cable termination of claim 13 further comprising: (a) theplate including a plurality of ground through apertures spaced from andsurrounding the at least one signal aperture, each of the groundapertures extending between the face surface and the device surface, theground apertures each having an anchor block opening in the face surfaceand a ground device opening in the device face; and (b) anelectrically-conductive compliant ground contact captured within each ofthe ground apertures, the ground contact having an anchor block contactpoint extending from the anchor block opening into electrical contactwith the ferrule and a ground device contact point extending from theground device opening.